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Subject[PATCH 22/47] staging/lustre/lov: to not hold sub locks at initialization
Date
From: Jinshan Xiong <jinshan.xiong@intel.com>

Otherwise, it will cause deadlock because it essentially holds
some sub locks and then to request others in an arbitrary order.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-on: http://review.whamcloud.com/9152
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
---
drivers/staging/lustre/lustre/lov/lov_lock.c | 36 +---------------------------
1 file changed, 1 insertion(+), 35 deletions(-)

diff --git a/drivers/staging/lustre/lustre/lov/lov_lock.c b/drivers/staging/lustre/lustre/lov/lov_lock.c
index 0bbe141..08ac374 100644
--- a/drivers/staging/lustre/lustre/lov/lov_lock.c
+++ b/drivers/staging/lustre/lustre/lov/lov_lock.c
@@ -346,41 +346,7 @@ static int lov_lock_sub_init(const struct lu_env *env,
}
}
LASSERT(nr == lck->lls_nr);
- /*
- * Then, create sub-locks. Once at least one sub-lock was created,
- * top-lock can be reached by other threads.
- */
- for (i = 0; i < lck->lls_nr; ++i) {
- struct cl_lock *sublock;
- struct lov_lock_link *link;

- if (lck->lls_sub[i].sub_lock == NULL) {
- sublock = lov_sublock_alloc(env, io, lck, i, &link);
- if (IS_ERR(sublock)) {
- result = PTR_ERR(sublock);
- break;
- }
- cl_lock_get_trust(sublock);
- cl_lock_mutex_get(env, sublock);
- cl_lock_mutex_get(env, parent);
- /*
- * recheck under mutex that sub-lock wasn't created
- * concurrently, and that top-lock is still alive.
- */
- if (lck->lls_sub[i].sub_lock == NULL &&
- parent->cll_state < CLS_FREEING) {
- lov_sublock_adopt(env, lck, sublock, i, link);
- cl_lock_mutex_put(env, parent);
- } else {
- OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
- cl_lock_mutex_put(env, parent);
- cl_lock_unhold(env, sublock,
- "lov-parent", parent);
- }
- cl_lock_mutex_put(env, sublock);
- cl_lock_put(env, sublock);
- }
- }
/*
* Some sub-locks can be missing at this point. This is not a problem,
* because enqueue will create them anyway. Main duty of this function
@@ -533,7 +499,7 @@ static int lov_lock_enqueue_one(const struct lu_env *env, struct lov_lock *lck,
static int lov_sublock_fill(const struct lu_env *env, struct cl_lock *parent,
struct cl_io *io, struct lov_lock *lck, int idx)
{
- struct lov_lock_link *link;
+ struct lov_lock_link *link = NULL;
struct cl_lock *sublock;
int result;

--
1.8.5.3


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